What is the function of "service disable-ip-fast-frag" command?

[Cown]

I can't seem to find any documentation for most of the service commands in relation to routers. So does anyone know the function of "service disable-ip-fast-frag" command and what it does exactly?

Regards.

[Mark Malone · Accepted solution]

It tells you in the router when you tab it out , it most likely a security feature to prevent fragmentation attacks that can occur on interfaces for ddos

disable-ip-fast-frag Disable IP particle-based fast fragmentation

IP fragmentation attacks are a common form of denial of service attack, in which the perpetrator overbears a network by exploiting datagram fragmentation mechanisms

[Cown]

Sort of the conclusion i came to, i'm just wondering why Cisco has no official description of the command. When i search for fragmentation attack on Cisco they recommend using ACLs to prevent that, so bit confused. 

[Mark Malone]

did you check the config guide for that release on the Cisco website , usually wherever the command is available there will be a short description by alphabetical order for each command and its use purpose

[Cown]

Link?

[Mark Malone]

you could try this link you would need to go into each topic an search for the service command unless you know which one it belongs too

https://www.cisco.com/c/en/us/support/routers/asr-1000-series-aggregation-services-routers/products-command-reference-list.html